1. Allow butter and egg whites to stand at room temperature for 30 minutes. Meanwhile, line twenty-four 2-1/2-inch muffin cups with paper bake cups (or coat with cooking spray). In a medium bowl stir together flour, baking powder, salt, and baking soda. In a 2-cup glass measuring cup combine buttermilk and cherry juice; set aside.
2. Preheat oven to 350 degrees F. In a large mixing bowl beat butter with an electric mixer on medium to high speed for 30 seconds. Add sugar, vanilla, and almond extract; beat until combined. Add egg whites, one at a time, beating well after each addition. Alternately add flour mixture and buttermilk mixture to beaten mixture, beating on low speed after each addition just until combined.
3. Spoon batter into prepared muffin cups, filling each about two-thirds full. Use the back of a spoon to smooth out batter in cups. Press a cherry half into batter in each cup.
4. Bake for 15 to 18 minutes or until tops spring back when lightly touched. Cool cupcakes in muffin cups on wire racks for 5 minutes. Remove cupcakes from muffin cups. Cool completely on wire racks.
5. Using a pastry bag fitted with a large star tip, pipe Cherry-Almond Butter Frosting over tops of cupcakes. If desired, top with cherries. Makes 24 (2-1/2-inch) cupcakes.
Cherry-Almond Butter Frosting: Allow 1/2 cup butter to stand at room temperature for 30 minutes. In a large mixing bowl beat butter with an electric mixer on medium speed until smooth. Gradually add 1 cup powdered sugar, beating well. Beat in 3 tablespoons maraschino cherry juice or milk and 1/2 teaspoon almond extract. Gradually beat in 3 cups additional powdered sugar. If necessary, beat in additional juice or milk, 1 teaspoon at a time, until frosting reaches a spreading consistency. Makes 2 cups frosting.
*Test Kitchen Tip: To make 3/4 cup sour milk, place 2 teaspoons lemon juice or vinegar in a glass measuring cup. Add enough milk to make 3/4 cup liquid; stir. Let the mixture stand for 5 minutes before using.